A compound having an optically active biphenylalanine structure is useful as an intermediate of medicaments such as a neutral endopeptidase inhibitor (cf. JP-H06-228187A and JP-2003-261522A).
The known methods for producing optically active biphenylalanine compounds are (1) a method including the steps of changing D-Boc-tyrosine methyl ester into triflate, subjecting the triflate to Suzuki coupling, and hydrolyzing the obtained ester (cf. U.S. Pat. No. 5,217,996) and (2) a method for synthesizing optically active Boc-biphenylalanine by asymmetric hydrogenation (cf. Chirality, 1996, Vol. 8, No. 2, p. 173-188 and JP-2003-261522A). However, as for the method (1), followings are known, that is, a reagent for making triflate is expensive, palladium as a catalyst used for Suzuki coupling is expensive, it is hard to remove residual palladium from a product, and D-tyrosine used as a raw material to make D-biphenylalanine is expensive. Therefore, the method (1) is not industrially effective. Further, the method (2) has a problem wherein a catalyst and an asymmetric source which are used for asymmetric hydrogenation are expensive.
On the other hand, as for a method for producing an optically active amino acid derivative, it is known to asymmetrically hydrolyze a racemate of N-(2,6-dimethylphenyl) alanine ester by using an enzyme (cf. WO2004/055195A). In addition, it is also known to produce an optically active amino acid or an optically active phenylalanine derivative by asymmetric hydrolysis using enzyme (cf. J. Chem. Technol. Biotechnol., 1994, Vol. 59, p. 61-65; ITE Letters on Batteries, New Technologies & Medicine, 2004, Vol. 5, No. 4, p. 377-380 ITE-Hohwa Inc.; Enantiomer, 2002, Vol. 7, No. 1, p. 1-3; Biotechnol. Lett., 1991, Vol. 13, No. 5, p. 317-322; and ES-547913A).
Further, it is known that N-substituted-L-amino acid and N-substituted-D-amino acid ester are produced by hydrolysis of racemic N-substituted-DL-amino acid ester by using protease in the presence of a weak base as a pH controlling reagent (cf. JP-H09-206089A).